Condition controller



Nov. 12,1940. c. HONEYWELL 2,221,636

CONDITION CONTROLLER Filed April 29, 1938 Jnomtor MurkC; HoneywellPatented Nov. 12, 1940 UNITED STATES conm'rron CONTROLLER Mark 04Honeywell, Wabash, Ind., assignor to Minneapolis-Honeywell RegulatorCompany, Minneapolis, Minm, a corporation oi Delaware Application April29, 1938, Serial No. 205,135

3 Claims. (01. 291-1) This invention relates in general to automaticcontrollers,'and is more particularly concerned with automaticcontrollers oi the type employing elongated flexible conditionresponsive material such, for instance, as humidity controllers.

The primary object of this invention is'the provision of a controller ofthis type which is simple and compact in construction, which is accuratein operation, which may readily be as-- 30 sembled to provide anydesired differential or operating range oi the instrument, and in whichthe responsive element may be readily replaced when necessary.

The above results are obtained by the provision ll of a rotatable drumupon which the condition responsive material is wound, the conditionre-- sponsive material being secured at one end to the drum, and at itsother end to a fixed support, to thereby cause rotation of the drum uponchange in value of the condition to which the ma terial responds. Thisrotation of the drum in turn is utilized to actuate a control device forthereby changing the position of said control de-' vice in accordancewith changes in value of said condition.

A more specific object of this invention, therefore, is the provision ofa condition controller of the type mentioned with a rotatable drum uponwhich the condition responsive material is mounted, and in which therotary motion of the drum resulting from change in value of thecondition is utilized for actuating a control device.

Other obiects'of this invention will become apparent from the followingdescription and the appended claims.

For a full disclosure of my invention, reference is made to thefollowing detailed description and to the accompanying drawing, in whichFigure l is a perspective of my improved humidity controller, showingthe instrument lying on its base plate, and in which Figure 2 is anelevational view partly in section.

Referring to the drawing, reference character I indicates the base platefor the instrument. This base plate may be mountedupon a wall or anysuitable support for the instrument. Mounted upon the base plate bymeans or posts 2 and 3 is a bracket member 4, this bracket member beingformed to provide ears 5 and 6 which project inwardly as'shown. Thebracket member 4 forms a support for a rotatable drum '7, this drumbeing carried by a pin or shaft 8 which is 68 secured to the bracketmember. The drum 1 may be formed in any suitable manner and is shown ascomprising front and rear plates 9 and it! which are secured together atthe center or hub of the drum. Mounted between the front and rear plates9 and iii are rollers I I, I2, and 5 llwhich may be supported bysuitable pins ex tending between these plates. The rollers H, l2, and I3are spaced around the drum as indicated and provide support for anelongated humidity responsive device or element It. This humidity 30responsive element may consist of a plurality of strands iii of hair orother moisture responsive material, these strands being secured togetherat one end by means of a clampingmember l6 and at the other end by means.of a clamping mem- 15 her I]. The clamping member i1 is securedto asuitable cross piece extending between the plates 9 and iii. The strandsl5 pass from this clamping member i'l over the rollers l2, I3 and i I tothe clamping member l6 which is secured 20 by a link is to an adjustingscrew l9 which is carried by the ear 6 of bracket member 4. The

adjusting screw I9 is provided with a head 20 and with an adjusting nut2|. The head 20 is urged away from the'ear 6 by means of a spring 25member 22 which is secured to the ear 6. This spring member 22,therefore, urges nut 2| against ear 6 at all times. By'this arrangement,it will be apparent that rotation of the adjusting nut 2| will causemovement of the adjusting screw 30 20 transversely oi the ear 6, therebychanging the position of the clamping member IS.

A spring 23 is attached at one end to a clip 24 carried by the rotatabledrum 7, and the other end of this spring is attached to the ear 5 ofbracket member This spring serves to urge the drum 1 in acounter-clockwise direction to thereby maintain the strands l5 of thehumidity I responsive element tent at all times. Upon change in relativehumidity, the strands I5 40 change in length. For instance, if thehumidity responsive element is formed of strands of hair, this materialwill increase in length as the relative humidity increases. Thisincrease in length of the strands l5 will permit counter-clockwise 45rotation of the drum 1 due to the action of the spring 23. Upon decreasein relative humidity, however, these strands will decrease in lengththereby causing rotation of the drum 1 against the action oi the spring23. 50

Reference character 25 indicates a U-shaped bracket which may be mountedupon the base plate I or upon any suitable support. Pivotally mounted inthe bracket 25 is a lever arm 26, this lever arm being provided with anear 2! which is as adapted to engage a pin 28 carried by the drum 1.This lever arm is also provided with a spring 29 for urging the armupwardly so as to maintain the car 21 in engagement with the pin 28.Lever arm 26 at its extremity carries a bailie member 30 which isadapted to engage a bleed port 3| which is mounted in a hollowprojection 32 secured to the base plate I. This hollow projection may beprovided with an opening plugged by a plug 33 for permitting insertionand removal of the bleed port element 3|.

It will be apparent that as the drum 1 rotates in a counter-clockwisedirection due to a change in relative humidity, the pin 28 will movedownwardly and this downward movement of the pin 28 will cause downwardmovement of the lever 26, this causing movement of the heme member 30away from the bleed port member I I This will increase the rate of bleedthrough the bleed port and consequently decrease the pressure in thecontrol system in a manner well understood in the art. Upon clockwiserotation of the drum I, however, the pin 28 will move upwardly therebypermitting upward movement oi the lever 2! by the spring 28, thiscausing the baiiie 3| to approach the bleed port member Ii and increasethe pressure within thepneumatic control system to which the instrumentis applied.

It will be apparent that. by changing the location oi the pin 28 on thedrum 1, the ratio of movement of drum I to movement oi lever 26 may bevaried. Thus it the pin ll is moved nearer to the center of the drum 7,there will be less movement of lever for a given movement of drum 1 thanwill occur with the pin II in the position shown. Thus by merelychanging the position of the pin 28 upon the drum I, the operating rangeor differential may be readily varied. If desired, the pin 18 instead ofbeing fixedly secured to the drum I may be adJustably secured thereto soas to permit readily adjustment of the range of the instrument.

It will be noted that with the construction above described, the drum 1and the humidity responsive element may be removed from the instrumentas aunit. This arrangement makes replacement oi. the humidity responsiveelement a very simple matter even when the instrument is in a relativelyinaccessible location.

From the foregoing description, it will be apparent that this inventionprovides a simple and compact humidity controller and further provides acontroller which may readily be assembled to provide any desiredoperating range or diflerential. While I have shown and described apreferred form of my invention; it will be understood that manymodifications of my invention will become apparent to those skilled inthe art. I, therefore, desire to be limited only by the scope of theappended claims.

I claim as my invention:

1. In a. condition controller, in combination, a drum member, mountingmeans for said drum member including a bearing for permitting rotaticnof said, drum member in a plane normal to said bearing, a plurality ofrollers mounted upon said drum member, said rollers being spaced fromeach other and having axes of rotation parallel to said bearing,elongated condition responsive material wound around said drurnmemberand riding upon said rollers, said material being adapted to change inlength upon change in the condition to which it responds to therebycause rotary movement of said drum member upon change in value of saidcondition, a control device, and means actuated by rotary movement orsaid drum member for actuating said control device.

2. In a condition controller, in combination, a rotatable member,mounting means for said member including a bearing for permittingrotation of said member in a plane normal to said bear- :5', saidmounting means providing for ready removal and replacement of saidmember, an elongated condition responsive element wound around saidrotatable member in the plane of rotation 01 said member. said elementbeing adapted to change in length upon change in value of the condition,having one end attached to the rotatable member and its other endattached to a relatively stationary support for thereby causing rotarymovement of said rotatable member upon change in value or saidcondition, the major portion oi said element being wound upon saidrotatable member andextending around said rotatable'member substantiallya full turn so that the element is almost entirely supported by saidrotatable member, said rotatable member including spaced supportingmeans for said element for permitting free circulation of fluid aboutall sides of the portion or the element carried by said rotatablemember, a control device, and means actuated by rotary movements oi saidrotatable member for actuating said control device.

3. In a condition controller, in combination, a rotatablemember,mounting means for said member including a bearing for permittingrotation of said member in a plane normal to said bearing, said mountingmeans providing for ready removal and replacement of said member, anelongated condition responsive element wound around said rotatablemember in the plane of rotation of said member, said element beingadapted to change in length upon change in value of the condition.having one end attached to the rotatable member and its other endattached to a relatively stationary support for thereby causing rotarymovement of said rotatable member upon change in value of saidcondition, the major portion of said element being wound upon saidrotatable member and extending around said rotatable membersubstantially a full turn so that the element is almost entirelysupported by said rotatable member, said rotatable member includingspaced supporting means for said element for permitting free circulationof fluid about all sides oi the portion of the element carried by saidrotatable member, a control device including a lever adjacent saidrotatable member, and a pin carried by said rotatable member andabutting said lever for causing movement of said lever upon rotation ofsaid rotatable member.

MARK C. HONEYWELL.

